Financial statements using an XBRL (extensible Business Reporting Language) document are requested to be submitted to Financial Services Agency. The XBRL document is a document described in XBRL which is an XML (extensible Markup Language)-based report description language related to, for example, financial reporting.
XBRL data used to create the XBRL document is changed according to, for example, amendment of laws, changes in accounting standards, and changes in the policy of the financial reporting of a supervisory organization of companies. The XBRL data includes a schema and a linkbase. The schema is a list of items used for the XBRL data, and defines a name and a data type of each item. The linkbase defines a relationship between items included in the schema. For example, the linkbase defines a relationship of a tree structure in which a plurality of child items hang from a parent item. Moreover, the linkbase defines order information as auxiliary information of a child item, so that a display order of the child item is determined by the order information. Items before and after a change are associated with each other using the XBRL data.
FIG. 15 is a diagram of an example in which items before and after a change are associated with each other using the XBRL data. FIG. 15 depicts XBRL data before the change and after the change. When an item name “CurrentAssets” in the XBRL data before the change is changed to an item name “CurrentAsset” in the XBRL data after the change, a mapping device that maps the items before and after the change focuses on a parent-child relationship, a sibling relationship, or auxiliary information between two items before and after the change. In FIG. 15, the mapping device compares parent items or sibling items in the items as targets for comparison, and determines that the item names of the parent items are the same “Assets” and the item names of the sibling items are also the same “NonCurrentAssets”. The mapping device produces a result that the item name “CurrentAssets” as the target for comparison has been changed to the item name “CurrentAsset” as the target for comparison, and associates the items before and after the change with each other (see, for example, Patent Document 1).
Patent Document 1: International Publication Pamphlet No. WO 2011/089683
However, there is a problem that when a plurality of pieces of information related to items in the XBRL data are changed, it is difficult to optimally associate the items before and after the change with each other. For example, when the item name of an item in the XBRL data is changed and the auxiliary information of the changed item is also changed, it is difficult to optimally associate the items before and after the change with each other.
FIG. 16 is a diagram of an example in which it is difficult to optimally associate items before and after the change with each other. FIG. 16 depicts the XBRL data before and after the change. When the item name “CurrentAssets” in the XBRL data before the change is changed to an item name “CurrentResources” in the XBRL data after the change, the mapping device focuses on a parent-child relationship, a sibling relationship, or pieces of auxiliary information between the two items before and after the change. In FIG. 16, the mapping device respectively compares parent items and sibling items of the items as targets for comparison with each other, and also compares pieces of label information as auxiliary information of the items with each other. The mapping device then determines that the item names of the parent items are the same as each other. However, the item names of the sibling items are “CurrentCosts” and “CurrentPrices”, which are not the same as each other. Moreover, both pieces of the label information are “Current Assets” and “Curent Assets”, that is, not all parts of both information match each other. Therefore, it is difficult for the mapping device to reliably produce a result such that the item name “CurrentAssets” as the target for comparison is changed to the item name “CurrentResources” as the target for comparison. Accordingly, it is difficult for the mapping device to optimally associate the items before and after the change with each other.